near-surface antenna
81Earth and Space Sciences — ▪ 1996 Introduction GEOLOGY AND GEOCHEMISTRY In 1995 significant developments took place in the realm of geologic mapping, which provides the foundation for the presentation and comparison of data in the Earth sciences. The most important… …
82Space-based solar power — Left: Part of the solar energy is lost on its way through the atmosphere by the effects of reflection and absorption. Right: Space based solar power systems convert sunlight to microwaves outside the atmosphere, avoiding these losses, and the… …
83Apollo Moon Landing hoax conspiracy theories — are claims that some or all elements of the Apollo Moon landings were faked by NASA and possibly members of other involved organizations. Some groups and individuals have advanced various theories which tend, to varying degrees, to include the… …
84Non-line-of-sight propagation — Non line of sight (NLOS) or near line of sight is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone. Many types of radio transmissions depend, to… …
85Signals intelligence — SIGINT redirects here. For the UNIX signal, see SIGINT (POSIX). RAF Menwith Hill, a large site in the United Kingdom, part of ECHELON and the UK USA Security Agreement. Signals intelligence (often contracted to SIGINT) is intelligence gathering… …
86Radiation pattern — Three dimensional antenna radiation patterns. The radial distance from the origin in any direction represents the strength of radiation emitted in that direction. The top shows the directive pattern of a horn antenna, the bottom shows the… …
87MIM-104 Patriot — Patriot system of the German Luftwaffe Type Mobile Surface to air missile system Place of …
88Semi-active radar homing — Semi active radar homing, or SARH, is a common type of missile guidance system, perhaps the most common type for longer range air to air and surface to air missile systems. The name refers to the fact that the missile itself is only a passive… …
89Skin effect — Skin depth redirects here. For the depth (layers) of biological/organic skin, see skin. Skin effect is the tendency of an alternating electric current (AC) to distribute itself within a conductor with the current density being largest near the… …
90Opportunity rover — (MER B) Opportunity in April 2003 Operator NASA Mission type Rover …
